Microwave-assisted stereoselective approach to novel steroidal ring D-fused 2-pyrazolines and an evaluation of their cell-growth inhibitory effects in vitro

• Microwave-assisted reactions of 16-dehydropregnenolone and hydrazines were carried out.
• Pyrazoline heteroring was introduced into ring D of the sterane nucleus.
• The reactions are assumed to proceed via hydrazone intermediates.
• Intramolecular ring-closures occurred in a stereoselective manner.
• Antiproliferative effects were determined in vitro on human gynecological cancer cell lines.

Novel ring D-condensed 2-pyrazolines in the Δ5-androstene series were efficiently synthesized from 16-dehydropregnenolone or its acetate with different arylhydrazines or methylhydrazine, respectively, under microwave irradiation. The reactions are assumed to occur via hydrazone intermediates, followed by intramolecular 1,4-addition leading to the fused heteroring stereoselectively with a 16α,17α-cis ring junction. The synthesized compounds were subjected to in vitro pharmacological studies of their antiproliferative activities against four human breast (MCF7, T47D, MDA-MB-231 and MDA-MB-361) and three cervical (HeLa, C33A and SiHA) malignant cell lines. Flow cytometry revealed that the most potent agent elicited a cell cycle disturbance.